Technical Field
This Patent Disclosure relates generally to digital to analog converters.
Related Art
Digital to Analog Converters (DACs) convert digital data into a sequence of impulses that are then processed by a reconstruction filter to band limit the DAC output, removing spurious high-frequency content. Reconstruction filters are also referred to as anti-imaging filters in that they prevent imaging by smoothing the DAC output waveform to remove image frequencies above the Nyquist limit. For example, in the case of RF transmitter applications, reconstruction filters remove DAC images prior to upconversion.
Reconstruction filters can be implemented with active RC filter circuits, avoiding the use of external inductors. Disadvantages of active reconstruction filters include power consumption, and sub-optimal noise and linearity.